Object detecting apparatus

ABSTRACT

An object detecting apparatus includes: a light projection unit that is an array light source in which each of a plurality of light emission areas emits light, an optical scanning unit that performs scanning with the light, which is emitted from the light projection unit, in a first direction, and a light receiving unit that receives reflected light which is the light, with which the scanning is performed, being reflected by an object, and an object information acquiring unit that detects presence/absence of the object based on emission timing at which the light is emitted from the light projection unit and light receiving timing at which the light receiving unit receives the reflected light.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/523,042 filed Oct. 24, 2014, which claims priority toJapanese Patent Application No. 2013-229222 filed in Japan on Nov. 5,2013 and Japanese Patent Application No. 2014-038590 filed in Japan onFeb. 28, 2014, the entire contents of each of which is incorporatedherein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an object detecting apparatus withwhich an object is detected.

2. Description of the Related Art

Recently, an object detecting apparatus to detect presence/absence of anobject or a distance to an object has been known. Object detectingapparatuses of various structures have been known.

For example, an object detecting apparatus which performstwo-dimensional scanning with a laser beam, selects only a reflectedlaser beam reflected by a detection object, and acquires distanceinformation related to the detection object based on timing ofprojecting the laser beam and timing of receiving the reflected laserbeam has been known (see, for example, JP 2010-096574 A).

Also, an object detecting apparatus which divides a visual field region,which is forward in a vehicle moving direction, in a right-leftdirection and performs, for example, presence/absence determination ofan obstacle in each of the divided visual field regions when performingpresence/absence determination of an obstacle, distance determination,or the like based on a reflected light of a laser beam emitted to thevisual field region has been known (see, for example, JP 2894055 B1).

Also, an object detecting apparatus including a rotary polygon mirror,which includes a plurality of reflection surfaces tilt angles of whichtoward a rotary shaft are different from each other, and a lightreceiving unit to receive a reflected light of a pulsed light emitted toa forward measurement area from the reflection surfaces has been known(see, for example, JP 3446466 B1).

In an object detecting apparatus, by dividing a visual field region inan up-down direction (vertical direction) when information related to an“object in a short detection distance” and an “object in a longdetection distance” is acquired, detection accuracy can be improved.

However, in an object detecting apparatus of each patent literaturedescribed above, it is difficult to divide a visual field region in anup-down direction (vertical direction) and to improve resolution of thedetection region.

Therefore, there is a need for an object detecting apparatus which canimprove resolution of a detection region by dividing a visual fieldregion in an up-down direction (vertical direction).

SUMMARY OF THE INVENTION

It is an object of the present invention to at least partially solve theproblems in the conventional technology.

The present invention provides an object detecting apparatus thatincludes a light projection unit that is an array light source in whicheach of a plurality of light emission areas emits light; an opticalscanning unit that performs scanning with the light, which is emittedfrom the light projection unit, in a first direction; and a lightreceiving unit that receives reflected light which is the light, withwhich the scanning is performed, being reflected by an object; and anobject information acquiring unit that detects presence/absence of theobject based on emission timing at which the light is emitted from thelight projection unit and light receiving timing at which the lightreceiving unit receives the reflected light. The above and otherobjects, features, advantages and technical and industrial significanceof this invention will be better understood by reading the followingdetailed description of presently preferred embodiments of theinvention, when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a vehicle mounting a laser radar which isan embodiment of an object detecting apparatus according to the presentinvention;

FIG. 2 is a configuration diagram illustrating a configuration exampleof a monitoring apparatus including the laser radar;

FIG. 3 is a configuration diagram illustrating a configuration exampleof the laser radar;

FIG. 4 is an optical arrangement view, on a YX plane, of a lightemitting system included in the laser radar;

FIG. 5 is an optical arrangement view, on a ZX plane, of the lightemitting system included in the laser radar;

FIG. 6 is an optical arrangement view, on the YX plane, of a lightdetecting system included in the laser radar;

FIG. 7 is an optical arrangement view, on the ZX plane, of the lightdetecting system included in the laser radar;

FIG. 8 is a plane view illustrating a configuration example of a lightsource included in the light emitting system;

FIG. 9 is a plane view illustrating a configuration example of a lightemission area included in the light source;

FIG. 10 is a view for describing an example of a scanning range of afirst rotary mirror included in the light emitting system;

FIG. 11 is an optical arrangement view illustrating a first arrangementexample, on the YX plane, of a light source and a coupling lens includedin the light emitting system;

FIG. 12 is a view of an optical path on an XY plane illustrating anexample of an optical path of light which passes the coupling lens inthe first arrangement example;

FIG. 13 is a view of an optical path on the YX plane illustrating anexample of an optical path of light emitted from the light emission areain the first arrangement example;

FIG. 14 is a view of an optical path on the ZX plane illustrating anexample of the optical path of the light emitted from the light emissionarea in the first arrangement example;

FIG. 15 is a view for describing a relationship between an irradiationregion of detection light and a detection distance of an object in thefirst arrangement example;

FIG. 16 is a view for describing a definition of an irradiation angle θ;

FIG. 17 is a view illustrating an example of a relationship between theirradiation angle θ and a detection distance on the YX plane in thefirst arrangement example;

FIG. 18 is a view illustrating a different example of the relationshipbetween the irradiation angle θ and the detection distance on the YXplane in the first arrangement example;

FIG. 19 is an optical arrangement view illustrating an example of anarrangement, on the YX plane, of an imaging forming lens and aphotodetector included in the light detecting system in the firstarrangement example;

FIG. 20 is a view for describing an example of a conjugate position ofthe photodetector in the first arrangement example;

FIG. 21 is a view of an optical path on the YX plane illustrating anexample of an optical path of reflected light which enters thephotodetector in the first arrangement example;

FIG. 22 is a view of an optical path on the ZX plane illustrating anexample of the optical path of the reflected light which enters thephotodetector in the first arrangement example;

FIG. 23 is a view illustrating an example of a relationship on the YXplane between an irradiation region and a detection region at aconjugate position of the photodetector in the first arrangementexample;

FIG. 24 is a view for describing an example of a detection angle α inthe first arrangement example;

FIG. 25 is an optical arrangement view illustrating a second arrangementexample, on the YX plane, of the light source and the coupling lensincluded in the laser radar;

FIG. 26 is a view for describing an example of a formed position of aconjugate image of the light source in the second arrangement example;

FIG. 27 is a view of an optical path on the YX plane illustrating anexample of an optical path of detection light in the second arrangementexample;

FIG. 28 is a view of an optical path on the ZX plane illustrating anexample of the optical path of the detection light in the secondarrangement example;

FIG. 29 is an optical arrangement view illustrating an example of apositional relationship between the imaging forming lens and thephotodetector in the second arrangement example;

FIG. 30 is a view of an optical path on the YX plane illustrating anexample of an optical path of reflected light in the second arrangementexample;

FIG. 31 is a view of an optical path on the ZX plane illustrating anexample of the optical path of the reflected light in the secondarrangement example;

FIG. 32 is a view for describing a relationship on the YX plane betweenan irradiation region and a detection region in the second arrangementexample;

FIG. 33 is a timing chart illustrating a relationship between lightemission timing in a light emission area and rotation timing of a firstrotary mirror which are included in the laser radar;

FIG. 34 is a timing chart illustrating a relationship between the lightemission timing of the light emission area and a scanning time aroundone reflection surface of the first rotary mirror;

FIG. 35 is a flowchart illustrating a flow of object informationacquiring processing executed by an object information acquiring unitincluded in the laser radar;

FIG. 36 is a configuration diagram illustrating an example of aconfiguration of a sound/alarm generation apparatus included in themonitoring apparatus;

FIG. 37 is a view illustrating a different example of a first rotarymirror and a second rotary mirror included in the laser radar; and

FIG. 38 is a view illustrating a different example of the first rotarymirror and the second rotary mirror included in the laser radar.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, an embodiment of an object detecting apparatusaccording to the present invention will be described with reference tothe drawings.

Embodiment of Monitoring Apparatus Including Object Detecting Apparatus

FIG. 1 is a schematic view of a vehicle 1 mounting a laser radar 20which is an embodiment of an object detecting apparatus according to thepresent invention. As illustrated in FIG. 1, the laser radar 20 isattached, for example, near a license plate in the front of the vehicle1. From the laser radar 20 attached to the front of the vehicle 1, lightis emitted forward of the vehicle 1. By the light, for example,detection of an object 100 (not illustrated in FIG. 1) which may be infront of the vehicle 1 or measurement of a distance to the object 100 isperformed.

First, a three-dimensional orthogonal coordinate system used fordescription of the following embodiment will be described with referenceto FIG. 1. As illustrated in FIG. 1, an irradiation surface of light(laser beam) emitted from the laser radar 20 attached to the front ofthe vehicle 1 becomes orthogonal to a road surface 2. A directionorthogonal to the road surface 2 (up-down direction on plane of paper)is assumed as a Z-axis direction. Also, a direction which is a forwarddirection (right direction on plane of paper) of the vehicle 1 and isorthogonal to the Z-axis direction is assumed as an X-axis direction.Also, a direction (depth direction on plane of paper) orthogonal to theZ-axis and the X-axis is assumed as a Y-axis direction. Note that theforward direction of the vehicle 1 (right direction on plane of paper)is assumed as a “+X direction”.

Embodiment of Monitoring Apparatus

Next, a monitoring apparatus 10 including the laser radar 20 will bedescribed. The monitoring apparatus 10 is, for example, a sensingapparatus mounted in the vehicle 1. A part of the monitoring apparatus10 is attached to an inner part of the vehicle 1 and the laser radar 20is attached to an outer part of the vehicle 1. FIG. 2 is a configurationdiagram illustrating a configuration example of the monitoring apparatus10 including the laser radar 20. As illustrated in FIG. 2, themonitoring apparatus 10 includes the laser radar 20, a display apparatus30, a main control apparatus 40, a memory 50, and a sound/alarmgeneration apparatus 60. Apparatuses included in the monitoringapparatus 10 are connected to each other in a manner mutuallycommunicable through a bus 70 for data transmission.

The display apparatus 30 is a display unit to display object informationor movement information calculated by calculation processing executed inthe main control apparatus 40.

The main control apparatus 40 acquires whether there is movement of theobject 100 in front of the vehicle 1 based on “object information” orthe like stored in the memory 50 which will be described later. Also,when the object 100 is moving, the main control apparatus 40 acquires“movement information” including a moving direction and a moving speedof the object 100. Also, the main control apparatus 40 outputs alarminformation based on the object information and the movementinformation. The alarm information is output when it is determined,based on the object information or the like, that “there is a danger” bycalculation processing executed in the main control apparatus 40.

The memory 50 is a storage unit to store “object information” acquiredby object information acquiring processing executed by the laser radar20.

The sound/alarm generation apparatus 60 outputs sound or an alarm signalaccording to the alarm information, which is output by the main controlapparatus 40 based on the object information and the movementinformation, and call attention around the vehicle 1.

FIG. 36 is a configuration diagram illustrating an example of aconfiguration of the sound/alarm generation apparatus 60. As illustratedin FIG. 36, the sound/alarm generation apparatus 60 includes a soundsynthesis apparatus 61, an alarm signal generation apparatus 62, and aspeaker 63.

The sound synthesis apparatus 61 is a sound output apparatus whichincludes a plurality of pieces of sound data, selects sound datacorresponding to the alarm information input from the main controlapparatus 40, and outputs the selected sound data to the speaker 63.

The alarm signal generation apparatus 62 is an alarm output apparatuswhich generates an alarm signal corresponding to the alarm informationinput from the main control apparatus 40 and outputs the generated alarmsignal to the speaker 63.

Configuration Example of Laser Radar 20

Next, a detail configuration of the laser radar 20 will be described.FIG. 3 is a configuration diagram illustrating a configuration exampleof the laser radar 20. As illustrated in FIG. 3, the laser radar 20includes a light emitting system 201, a light detecting system 202, andan object information acquiring unit 203.

The light emitting system 201 is an optical system to emit detectionlight Li to the object 100. The detection light Li is emitted in the +Xdirection. The light detecting system 202 is an optical system to detectreflected light Lr which is the detection light Li reflected by theobject 100. The light emitting system 201 and the light detecting system202 are arrayed in line in the Z-axis direction. The light emittingsystem 201 is arranged on a +Z side of the light detecting system 202.

The object information acquiring unit 203 controls an operation of eachof the light emitting system 201 and the light detecting system 202.Also, the object information acquiring unit 203 is connected to a maincontrol apparatus 40 in a communicable manner through the bus 70 andmutually communicates various kinds of information with the main controlapparatus 40 through the bus 70.

The object information acquiring unit 203 makes the light emittingsystem 201 and the light detecting system 202 operate and executes the“object information acquiring processing”. By the object informationacquiring processing, the object information acquiring unit 203 acquiresa detection result of the reflected light Lr in the light detectingsystem 202. Based on the acquired detection result, the objectinformation acquiring unit 203 acquires information (hereinafterreferred to as “object information”) related to presence/absence of theobject 100, a distance to the object 100, a size of the object 100, ashape of the object 100, a position of the object 100, and the like. Theobject information acquired in the object information acquiring unit 203is stored into the memory 50. A detail processing flow of the objectinformation acquiring processing will be described later.

Note that the object information acquiring unit 203, the light emittingsystem 201, and the light detecting system 202 are housed in a chassis(not illustrated).

Configuration Example of Light Emitting System 201

Next, a configuration of the light emitting system 201 will bedescribed. FIG. 4 and FIG. 5 are optical arrangement views illustratingan example of the light emitting system 201. FIG. 4 is an opticalarrangement view of the light emitting system 201 on the YX plane. FIG.5 is an optical arrangement view of the light emitting system 201 on theZX plane.

As illustrated in FIG. 4 and FIG. 5, the light emitting system 201includes a light source 21, a coupling lens 22, a first reflectionmirror 23, and a first rotary mirror 24.

First, the light source 21 will be described. FIG. 8 is a plane viewillustrating a configuration example of the light source 21. Asillustrated in FIG. 8, the light source 21 is a light projection unitincluding an array light source and includes a plurality of lightemission areas 211. The light emission areas 211 are arranged in theZ-axis direction. The light emission areas 211 are arranged at regularintervals. A shape of each light emission area 211 is a square.

In the following description, in a case of distinguishing the pluralityof light emission areas 211, which is included in the light source 21,from each other and referring to a specific light emission area 211, thespecific light emission area 211 will be simply referred to as A (i).Here, i indicates an order of the light emission area 211 in the array,from an edge in the Z-axis direction, in the light source 21. Forexample, when the light source 21 includes 28 light emission areas 211,the light emission areas 211 included in the light source 21 are A (1)to A (28).

It is assumed that a length of one side of one light emission area 211is d1. Also, it is assumed that a gap between adjacent light emissionareas 211 is d2. Note that d1 which is the length of one side of onelight emission area 211 is determined by the number of light emissionunits 2111 arranged in the one light emission area 211.

FIG. 9 is a plane view illustrating a configuration example of the onelight emission area 211. As illustrated in FIG. 9, each of the lightemission areas 211 is an aggregation of the plurality of light emissionunits 2111. The light emission units 2111 are arrayed two-dimensionally.Note that a shape of each of the light emission units 2111 is a square.

In the following description, it is assumed that there are 150 lightemission units 2111 arrayed in the Y-axis direction and 150 lightemission units 2111 arrayed in the Z-axis direction in one lightemission area 211. That is, one light emission area 211 includes 22500light emission units 2111.

It is assumed that a length of one side of each light emission unit 2111is d3. Also, a gap between adjacent light emission units 2111 is d4.

In the light source 21, the length of d2 which is a gap between theadjacent light emission areas 211 is set as about 0.02 mm. Also, d3which is the length of one side of each light emission unit 2111 is setas about 0.7 μm and the length of d4 which is a gap between the adjacentlight emission units 2111 is set as about 1 μm.

Each of the light emission units 2111 is a vertical cavity surfaceemitting laser (VCSEL). That is, the light source 21 including the lightemission units 2111, each of which is a VCSL, is so-called a surfaceemitting laser array.

Turning on and off of the light emission units 2111 are controlled bythe object information acquiring unit 203. That is, lighting control ofthe light emission areas 211 is performed by the object informationacquiring unit 203. An emitting direction of light emitted from thelighted light emission units 2111 is the +X direction.

Description goes back to FIG. 4 and FIG. 5. The coupling lens 22 isarranged on a side in the +X direction of the light source 21. Note thatinstead of the coupling lens 22, a coupling optical system including afunction equivalent to that of the coupling lens 22 may be arranged. Inthis case, the coupling optical system may include a plurality ofoptical elements.

To improve accuracy of object information by using the laser radar 20,it is necessary to improve emission power of the light emitted from thelight source 21. Therefore, it is necessary to increase the emissionpower of the light source 21. However, it is difficult to increase theemission power of the light emission units 2111 in principle.

As a method to increase the emission power of the light source 21, thereis a method to configure the light source 21 with the light emissionunits 2111 integrated two-dimensionally. In this case, when emissionpower of one light emission unit 2111 is 1 mW, emission power of 22.5 Wcan be acquired by integrating 22500 light emission units 2111.

In the present embodiment, the light source 21 includes 28 lightemission areas 211. Thus, the number of times of division of detectionin the vertical direction (Z-axis direction) is set to “28”. In such amanner, when the number of times of division can be increased, objectinformation corresponding to a purpose of a user can be acquired.

For example, as illustrated in FIG. 1, when the laser radar 20 ismounted in the vehicle 1, object detection can be performed by dividinga visual field region of a driver of the vehicle 1 in the verticaldirection (Z-axis direction). By receiving, with a photodetector 29, thereflected light Lr of pieces of the detection light Li respectivelyemitted from the 28 light emission areas 211 arrayed in the Z-axisdirection, object information corresponding to the number (28) of thelight emission areas 211 can be acquired. In such a manner, by usingpieces of the detection light Li from the plurality of light emissionareas 211 arrayed in the Z-axis direction of the visual field region(detection region), a plurality of pieces of the reflected light Lr isreceived. Thus, object information can be acquired in more detail.

Also, 28 light emission areas 211 arrayed in the vertical direction(Z-axis direction) can be classified into two groups when used. Forexample, 20 light emission areas 211 which are A (1) to A (20) are usedfor detection processing of the object 100 in the visual field region.On the other hand, eight light emission areas 211 which are A (21) to A(28) are used for detection processing of the object 100 on the roadsurface 2. In such a manner, by classifying the light emission areas 211into two or more groups and forming detection region groups, a differentobject can be detected in each detection region.

In such a case, distance information included in the object informationon the road surface 2 can also be used, for example, by calculating atilt thereof, for calibration of a horizontal component (Y-axisdirection) in acquiring distance information in the visual field region.Alternatively, information related to a distance to the object 100 onthe road surface 2 can also be used for calculation of a saferinter-vehicular distance by being associated with a breaking distance inbreaking. Also, trouble of the laser radar 20 or grime on a lightreceiving surface can be detected by calculating a quantity of thereflected light.

The first reflection mirror 23 is a reflection member to reflect light,which has passed the coupling lens 22, to the first rotary mirror 24.

The first rotary mirror 24 is an optical scanning unit and is a polygonmirror including a plurality of mirror surfaces (reflection surfaces)which rotates around a rotary shaft. The rotary shaft of the firstrotary mirror 24 is parallel to the Z-axis. By the plurality ofreflection surfaces included in the first rotary mirror 24, light fromthe first reflection mirror 23 is reflected in the X-axis direction.Each reflection surface of the first rotary mirror 24 is parallel to therotary shaft. As illustrated in FIG. 4 and FIG. 5, the first rotarymirror 24 includes four reflection surfaces.

The light reflected by the reflection surfaces of the first rotarymirror 24 is scanned optically in the Y-axis direction, which is a firstdirection, by the rotation of the first rotary mirror 24. Rotationcontrol of the first rotary mirror 24 is performed by the objectinformation acquiring unit 203. Here, the light reflected by thereflection surfaces of the first rotary mirror 24 is the “detectionlight Li” emitted from the laser radar 20.

FIG. 10 is a view for describing an example of a scanning range of thefirst rotary mirror 24 included in the light emitting system 201. Asillustrated in FIG. 10, a moving direction of the detection light Livaries on the YX plane orthogonal in the Z-axis direction by therotation of the first rotary mirror 24. By the detection light Li, ascanning range is scanned in a +Y direction. That is, the scanningregion is scanned in the Y-axis direction which is the first direction.

Note that as illustrated in FIG. 10, on the YX plane, an angle formed bydetection light Li moving toward an edge on a −Y side of the scanningregion and detection light Li moving toward an edge on the +Y side ofthe scanning region is also called a scanning angle φ. The scanningregion by the detection light Li which forms the scanning angle φ is arange scanned by one of the reflection surfaces of the first rotarymirror 24.

When there is the object 100 (not illustrated) in the scanning rangeillustrated in FIG. 10, a part of the detection light Li is reflected bythe object 100. Apart of the reflected light returns to the laser radar20. The light which is reflected by the object 100 and returns to thelaser radar 20 is the reflected light Lr.

Configuration Example of Light Detecting System 202

Next, a configuration of the light detecting system 202 will bedescribed. FIG. 6 and FIG. 7 are optical arrangement views illustratingan example of the light detecting system 202. FIG. 6 is an opticalarrangement view of the light detecting system 202 on the YX plane. FIG.7 is an optical arrangement view of the light detecting system 202 onthe ZX plane.

As illustrated in FIG. 6 and FIG. 7, the light detecting system 202includes a second rotary mirror 26, a second reflection mirror 27, animaging forming lens 28, and the photodetector 29.

The second rotary mirror 26 is a polygon mirror including a plurality ofmirror surfaces (reflection surfaces) which rotates around the rotaryshaft. Similarly to the first rotary mirror 24, the second rotary mirror26 includes a rotary shaft parallel to the Z-axis. Each of the pluralityof reflection surfaces included in the second rotary mirror 26 isparallel to the rotary shaft. As illustrated in FIG. 6 and FIG. 7, thesecond rotary mirror 26 includes four reflection surfaces.

The reflected light Lr which is a part of the detection light Lireflected by the object 100 is reflected by the reflection surfaces ofthe second rotary mirror 26 and moves toward a mirror surface of thesecond reflection mirror 27. Rotation control of the second rotarymirror 26 is performed by the object information acquiring unit 203.

The second reflection mirror 27 is a reflection member to reflect thelight from the second rotary mirror 26 in a −X direction.

The imaging forming lens 28 is arranged on the −X side of the secondreflection mirror 27 and is a condenser lens to condense the lightreflected by the second reflection mirror 27.

The photodetector 29 is a light receiving unit to receive the lightwhich passes the imaging forming lens 28. The photodetector 29 outputs,to the object information acquiring unit 203, a signal corresponding toa quantity of the received light (received light quantity). When anoutput level of the signal from the photodetector 29 is equal to orhigher than a threshold set in advance, the object information acquiringunit 203 determines that the light detecting system 202 receives thereflected light Lr from the object 100. As a light receiving elementincluded in the photodetector 29, an avalanche photodiode (APD) or a pinphotodiode (PD) can be used.

Rotating operations of the first rotary mirror 24 and the second rotarymirror 26 are synchronized by control by the object informationacquiring unit 203. That is, the first rotary mirror 24 and the secondrotary mirror 26 are controlled to have the same rotation angle. Arotation angle sensor (such as hall element) to detect a rotation angleis provided to each of the first rotary mirror 24 and the second rotarymirror 26. An output signal from each of the rotation angle sensors istransmitted to the object information acquiring unit 203. Based on theoutput signal from each of the rotation angle sensors, the objectinformation acquiring unit 203 detects a rotation angle of each of thefirst rotary mirror 24 and the second rotary mirror 26.

As described above, the object information acquiring unit 203 includedin the laser radar 20 controls an operation of turning on and turningoff the light source 21 and also controls rotating operations of thefirst rotary mirror 24 and the second rotary mirror 26.

Also, based on the output signal from the photodetector 29, the objectinformation acquiring unit 203 acquires information related topresence/absence of the object 100 and executes processing to determinewhether there is the object 100. Also, when the object informationacquiring unit 203 determines that “there is the object 100”, the objectinformation acquiring unit 203 executes processing to acquire “objectinformation” including, for example, a distance to the object based onlighting timing of the light source 21 and light receiving timing in thephotodetector 29. In other words, the object information acquiring unit203 executes processing to detect presence/absence of an object based ontiming at which the light is emitted from the light emission areas 211and timing at which the photodetector 29 receives the reflected light.

Note that the first rotary mirror 24 included in the light emittingsystem 201 and the second rotary mirror 26 included in the lightdetecting system 202 may be integrated.

FIG. 37 is a view illustrating a different example of the first rotarymirror 24 and the second rotary mirror 26. As illustrated in FIG. 37,the first rotary mirror 24 and the second rotary mirror 26 may includethe same rotary shaft and the first rotary mirror 24 and the secondrotary mirror 26 may be arranged in the Z-axis direction.

Also, FIG. 38 is a view illustrating a different example of the firstrotary mirror 24 and the second rotary mirror 26. As illustrated in FIG.38, the first rotary mirror 24 and the second rotary mirror 26 mayinclude reflection surfaces in common. In this case, the reflectionsurfaces of the first rotary mirror 24 and the reflection surfaces ofthe second rotary mirror 26 are distinguished from each other accordingto a position in the Z-axis direction.

First Arrangement Example of Coupling Lens 22 and Imaging Forming Lens28

Next, an example of an optical arrangement of the coupling lens 22 andthe imaging forming lens 28 included in the laser radar 20 will bedescribed. First, an example of an optical arrangement of the lightsource 21 and the coupling lens 22 included in the light emitting system201 will be described. FIG. 11 is an optical arrangement viewillustrating a first arrangement example, on the YX plane, of the lightsource 21 and the coupling lens 22.

As illustrated in FIG. 11, the coupling lens 22 is arranged in the +Xdirection of the light source 21. A distance between the coupling lens22 and the light source 21 is identical to a focal length (f1) of thecoupling lens 22. That is, when seen from the light source 21, thecoupling lens 22 is arranged at a position which is away therefrom by adistance corresponding to the focal length (f1).

When the distance between the coupling lens 22 and the light source 21is identical to the focal length (f1) of the coupling lens 22, lightemitted from one of the light emission units 2111 in one light emissionarea 211 included in the light source 21 becomes substantially parallellight by the coupling lens 22.

However, since the light source 21 includes a plurality of lightemission units 2111 in one light emission area 211, when the pluralityof light emission units 2111 is lighted simultaneously, light which haspassed the coupling lens 22 does not become the parallel light. It isbecause an optical path of light emitted from a light emission unit 2111arranged at a lower end in the Z-axis direction of the one lightemission area 211 and that of light emitted from a light emission unit2111 arranged at an upper edge in the Z-axis direction thereof areslightly different from each other.

FIG. 12 is a view of an optical path illustrating an example of anoptical path of the light emitted from the plurality of light emissionunits 2111 simultaneously in the first arrangement example. Asillustrated in FIG. 12, when the plurality of light emission units 2111included in one of the light emission areas 211 in the light source 21is lighted simultaneously, apiece of light emitted from each of thelight emission units 2111 becomes parallel light after passing thecoupling lens 22. However, the light, which is emitted from the onelight emission area 211, as a whole becomes divergent light bypassingthe coupling lens 22. However, a formed position of a conjugate image ofthe light source 21 by the coupling lens 22 is at infinity.

FIG. 13 is a view of an optical path illustrating an example of anoptical path, on the YX plane, of the light emitting system 201 in thefirst arrangement example. FIG. 14 is a view of an optical pathillustrating an example of an optical path on the ZX plane in the firstarrangement example of the light emitting system 201.

As illustrated in FIG. 13 and FIG. 14, the light emitted from the onelight emission area 211 passes the coupling lens 22 and becomes thedivergent light. Then, the light is emitted through the first reflectionmirror 23 and the first rotary mirror 24. That is, the detection lightLi emitted from the laser radar 20 is the divergent light.

FIG. 15 is a view for describing a relationship between an irradiationregion of the detection light Li and a detection distance of the object100. As illustrated in FIG. 15, a divergent degree of the detectionlight Li is increased as a distance from the light source 21 becomeslonger. That is, a spread of the detection light Li in the Y directionon the YX plane becomes wider as the detection distance becomes longer.In such a manner, a spread (size) of the irradiation region of thedetection light Li in the Y-axis direction is different according to adetection distance.

Thus, in the laser radar 20, the irradiation region of the detectionlight Li is different according to a distance to the object 100. Notethat in a lighted region in a stricter manner, it is necessary todistinguish the irradiation region according to a distance (detectiondistance) to the detected object 100. However, in the followingdescription, in order to avoid complexity, the irradiation region, as awhole, by the detection light Li will be simply referred to as an“irradiation region” without being distinguished by a detectiondistance.

Here, an “irradiation angle” will be defined as what indicates a spreadof the irradiation region. FIG. 16 is a view for describing a definitionof the irradiation angle. As illustrated in FIG. 16, light emitted fromone of the light emission areas 211 included in the light source 21passes the coupling lens 22 and diverges, whereby the light becomes thedetection light Li. When a spread of a lighted region in a certaindistance is seen with a center of the coupling lens 22 as a viewpoint,an angle θ formed by the detection light Li which forms the lightedregion is an “irradiation angle”.

FIG. 17 is a view illustrating an example of a relationship between acertain detection distance and an irradiation angle 9 on the YX plane inthe first arrangement example. FIG. 18 is a view illustrating adifferent example of a relationship between a certain detection distanceand an irradiation angle θ on the YX plane in the first arrangementexample. When FIG. 17 and FIG. 18 are compared, a detection distancefrom the center of the coupling lens 22 is shorter in the example inFIG. 17 and is longer in the example illustrated in FIG. 18. A spread ofthe irradiation region on a YZ plane is narrower in the exampleillustrated in FIG. 17 and is wider in the example illustrated in FIG.18. Also, an irradiation angle θ is larger in the example illustrated inFIG. 17 and is smaller in the example illustrated in FIG. 18. That is,the irradiation angle θ becomes larger as a detection distance becomesshorter, and becomes smaller as a detection distance becomes longer.

Next, an example of an optical arrangement of the imaging forming lens28 and the photodetector 29 included in the light detecting system 202will be described. FIG. 19 is an optical arrangement view illustrating arelationship on the YX plane between the imaging forming lens 28 and thephotodetector 29 in the first arrangement example. As illustrated inFIG. 19, the imaging forming lens 28 is arranged in the +X direction ofthe photodetector 29. A distance between the imaging forming lens 28 andthe photodetector 29 is longer than a focal length (f2) of the imagingforming lens 28. That is, the photodetector 29 is arranged in a positionfarther than the focal length (f2) when seen from the imaging forminglens 28.

Next, a position of a conjugate image of the photodetector 29 in thefirst arrangement example will be described. FIG. 20 is a view fordescribing a conjugate position of the photodetector 29 in the firstarrangement example. As illustrated in FIG. 20, when the photodetector29 is an object point, since a distance between the imaging forming lens28 and the photodetector 29 is longer than the focal length (f2) of theimaging forming lens 28, an image of the photodetector 29 is formed at acertain detection distance. It is assumed that the detection distance atwhich the image of the photodetector 29 is formed is Px. That is, aposition in the +X direction, a distance to which position from thelaser radar 20 is Px, becomes a formed position of the conjugate imageof the photodetector 29 by the imaging forming lens 28. In the followingdescription, is assumed that Px is “80 m”.

Next, an optical path of the reflected light Lr in the first arrangementexample will be described. FIG. 21 is a view of an optical pathillustrating an example of an optical path, on the YX plane, of thereflected light which enters the photodetector in the first arrangementexample. FIG. 22 is a view of an optical path illustrating an example ofthe optical path, on the ZX plane, of the reflected light which entersthe photodetector in the first arrangement example.

As illustrated in FIG. 21 and FIG. 22, the reflected light Lr from theobject 100 is reflected by the second rotary mirror 26 and the secondreflection mirror 27, passes the imaging forming lens 28, and isreceived by the photodetector 29. The conjugate image of thephotodetector 29 is formed at a position at a distance corresponding toPx.

According to the coupling lens 22 and the imaging forming lens 28 whichhave been described above in the first arrangement example, theconjugate image of the light source 21 is formed at infinity and theconjugate image of the photodetector 29 is formed near the laser radar20.

FIG. 23 is a view illustrating a relationship between an irradiationregion and a detection region at the conjugate position of thephotodetector 29 on the YX plane in the first arrangement example. Asillustrated in FIG. 23, in the first arrangement example, when spreadsof a lighted region and a detection region in the Y direction at aposition at which a detection distance is Px are compared, the spread ofthe detection region in the Y direction becomes narrower than the spreadof the lighted region in the Y direction at the detection distance (Px)which becomes the conjugate position of the photodetector 29.

That is, when the object 100 is at a position which is in the Xdirection of the laser radar 20 at the distance “Px” and a distance towhich in the Y-axis direction corresponds to the inside of the conjugateimage of the photodetector 29, the photodetector 29 receives thereflected light Lr from the object 100. In other words, in the firstarrangement example, a region in which the conjugate image of thephotodetector 29 is formed corresponds to a “detection region” in whichthe object 100 can be detected by the reflected light Lr of when thedetection light Li is emitted to the object 100.

Here, a “detection angle” will be defined as what indicates a spread ofthe detection region. FIG. 24 is a view for describing a definition ofthe detection angle in the first arrangement example. As illustrated inFIG. 24, when a spread of the detection region at a position at adistance Px, is seen with a center of the coupling lens 22 as aviewpoint, an angle α which is formed at the center of the coupling lens22 is the “detection angle”.

The detection angle is substantially constant at a position where thedetection distance is Px or longer. Also, within a range of a detectiondistance requested to the laser radar 20, a size of the detection regionis smaller than that of the lighted region. Thus, the laser radar 20 candivide the lighted region further smaller and set each of the dividedlighted regions as the detection region. That is, the laser radar 20 canimprove detection resolution.

Note that at a position where the detection distance is shorter than Px,the detection region becomes larger than the detection region in Px.That is, a size of the detection region becomes the smallest in Px.Thus, Px may be set as the shortest detection distance. In this case,the object information acquiring processing executed in the objectinformation acquiring unit 203 can be simplified.

Second Arrangement Example of Coupling Lens 22 and Imaging Forming Lens28

Next, a different example of an optical arrangement of the coupling lens22 and the imaging forming lens 28 included in the laser radar 20 willbe described. First, a different example of an optical arrangement ofthe light source 21 and the coupling lens 22 included in the lightemitting system 201 will be described. FIG. 25 is an optical arrangementview illustrating a second arrangement example, on the YX plane, of thelight source 21 and the coupling lens 22.

As illustrated in FIG. 25, the coupling lens 22 according to the secondarrangement example is arranged in the +X direction of the light source21 and a distance thereto is longer than the focal length (f1) of thecoupling lens 22.

FIG. 26 is a view for describing a formed position of a conjugate imageof the light source 21 in the second arrangement example. As illustratedin FIG. 26, in the second arrangement example, a formed position of theconjugate image of the light source 21 by the coupling lens 22 is at thedistance “Px” described in the first arrangement example.

Next, an optical path of the detection light Li in the secondarrangement example will be described. FIG. 27 is a view of an opticalpath illustrating an example of an optical path of the detection lightLi on the YX plane in the second arrangement example. FIG. 28 is a viewof an optical path illustrating an example of an optical path of thedetection light Li on the ZX plane in the second arrangement example. Asillustrated in FIG. 27 and FIG. 28, after passing the coupling lens 22,light emitted from one of the light emission areas 211 included in thelight source 21 converges toward the distance Px which is a formedposition of the conjugate image of the light source 21. That is, animage of the detection light Li is formed at the distance Px.

Next, a different example of an optical arrangement of the imagingforming lens 28 and the photodetector 29 included in the light detectingsystem 202 will be described. FIG. 29 is an optical arrangement viewillustrating an arrangement example of the imaging forming lens 28 andthe photodetector 29 in the second arrangement example. As illustratedin FIG. 29, the imaging forming lens 28 is arranged in the +X directionof the photodetector 29 and a distance thereto is identical to the focallength (f2) of the imaging forming lens 28. That is, when seen from theimaging forming lens 28, the photodetector 29 is arranged at a positionwhich is away therefrom by a distance corresponding to the focal length(f2).

FIG. 30 is a view of an optical path illustrating an example of anoptical path of the reflected light Lr on the YX plane in the secondarrangement example. FIG. 31 is a view of an optical path illustratingan example of an optical path of the reflected light Lr on the ZX planein the second arrangement example. As illustrated in FIG. 30 and FIG.31, the reflected light Lr from the object 100 is reflected by thesecond rotary mirror 26 and the second reflection mirror 27 and passesthe imaging forming lens 28, and then, an image thereof is formed on thephotodetector 29.

According to the second arrangement example described above, theconjugate image of the light source 21 is formed near the laser radar 20and the conjugate image of the photodetector 29 is formed at infinity.

FIG. 32 is a view illustrating a relationship between an irradiationregion and a detection region on the YX plane in the second arrangementexample. As illustrated in FIG. 32, in the second arrangement example,all pieces of the reflected light Lr from the object 100 can be receivedin the photodetector 29. That is, in the second arrangement example, theirradiation region and the detection region are identical to each other.

A size of the detection region in the second arrangement example is thesame with a size of the detection region in the first arrangementexample. That is, also in the second arrangement example, an effectequivalent to that of the above described first arrangement example canbe acquired.

In other words, a region in which the object 100 can be detected is aregion in which an image of the light source 21 (hereinafter, alsoreferred to as “light source image”) and an image of the photodetector29 (hereinafter, also referred to as “detector image”) overlaps witheach other. Thus, as described in the first arrangement example, evenwhen a position of the object 100 is within the region of the lightsource image, the reflected light Lr from the object 100 is not lead tothe photodetector 29 when the position of the object 100 is outside theregion of the detector image. In this case, the object 100 is notdetected.

On the other hand, such as a case of the second arrangement example,even when a position of the object 100 is within the region of thedetector image, light (detection light Li) emitted from the light source21 is not emitted to the object 100 when the object 100 is outside theregion of the light source image. In this case, the reflected light Lrfrom the object 100 is not generated. Thus, there is no light detectablein the photodetector 29.

First Spatial Information Acquiring Method

Next, a method to acquire spatial information by using the laser radar20 will be described. As described, the light source 21 of the laserradar 20 includes the plurality of light emission areas 211. FIG. 33 isa timing chart illustrating a relationship between light emission timingof the light emission areas 211 and rotation timing of the first rotarymirror 24. The laser radar 20 acquires, with the detection light Liemitted from one of the reflection surfaces of the first rotary mirror24, object information in a scanning range in an arbitrary regiondivided in the vertical direction (Z-axis direction).

That is, control of pulse-lighting of the light emission areas 211 isexecuted by the object information acquiring unit 203. Also, rotationcontrol of the first rotary mirror 24 is executed by the objectinformation acquiring unit 203. By the pulse-lighting of the lightemission areas 211, the detection light Li is emitted. That is, within aperiod of time in which scanning is performed with the detection lightLi by one of the reflection surfaces of the first rotary mirror 24, oneof the 28 light emission areas 211 is pulse-lighted. In other words, theobject information acquiring unit 203 determines which light emissionarea 211 to be lighted according to the rotation of the first rotarymirror 24. With the detection light Li, object information is acquired.

When the scanning time by the one reflection surface of the first rotarymirror 24 is over, the object information acquiring unit 203 gives alighting instruction on a next light emission area 211. Light emittedfrom the light emission area 211 according to the lighting instructionis used for scanning by a next reflection surface of the previousreflection surface of the first rotary mirror 24 and becomes thedetection light Li. Similarly to the previous stage, with the detectionlight Li, object information in the scanning range is acquired.

As described above, positions of the light emission areas 211 lightedaccording to rotation timing of the first rotary mirror 24 are differentin the vertical direction (Z-axis direction). In other words, in thelight source 21 configured as the array light source, the plurality oflight emission areas 211 is arrayed in a direction (Z-axis direction)different from the Y-axis direction which is the first direction.Lighting timing of each of the light emission areas 211 is determinedaccording to a detection region.

As described above, by repeating processing of lighting different lightemission areas 211 according to rotation timing of the first rotarymirror 24, the laser radar 20 executes detection processing of objectinformation in a whole visual field region.

The number of reflection surfaces of the first rotary mirror 24 is four.Thus, until the laser radar 20 acquires object information of the wholevisual field region, the first rotary mirror 24 is rotated, at least,for seven times.

Second Spatial Information Acquiring Method

Here, a case of acquiring and updating information of the whole visualfield region at every 21 ms will be considered. By rotating the firstrotary mirror 24 for seven times, one piece of object information can beacquired. Thus, the laser radar 20 cannot acquire the object informationunless the first rotary mirror 24 is rotated at 20000 rpm (1÷(21ms÷7÷1000÷60)). However, 20000 rpm is a significant number of rotations.Thus, when the first rotary mirror 24 is rotated at 20000 rpm, variousproblems are generated. For example, an operation of the laser radar 20becomes unstable and power consumption becomes large.

Thus, in the laser radar 20, object information acquiring processing toscan the whole visual field region is executed not in a scanning rangeof the plurality of reflection surfaces included in the first rotarymirror 24 but in that of one reflection surface among the plurality ofreflection surfaces included in the first rotary mirror 24. In otherwords, the laser radar 20 executes the object information acquiringprocessing in a scanning region defined by a scanning angle ϕ by one ofthe reflection surfaces of the first rotary mirror 24. The number ofrotations of the first rotary mirror 24 in this case only needs to be714.3 rpm (1÷(21 ms×4÷1000÷60)).

Thus, when processing of acquiring object information of the wholevisual field region can be executed by scanning by one reflectionsurface of the first rotary mirror 24, the number of rotations of thefirst rotary mirror 24 can be very small.

For example, when resolution in the scanning direction (Y-axisdirection) of the laser radar 20 is 0.24°, the object informationacquiring processing in the whole visual field region is executed whileone reflection of the first rotary mirror 24 rotates by 0.24°. That is,a range (scanning angle φ) scanned by one reflection surface of thefirst rotary mirror 24 is set as a rotation angle of the first rotarymirror 24 and is divided by 0.24°. That is, a range scanned by onereflection surface is divided into a plurality of regions (scanningregions). Within one of the divided plurality of regions (0.24°), alight emission area 211 to project the detection light Li is switched.Note that a period of time in which one mirror surface of the firstrotary mirror 24 rotates by 0.24° is 28 μs (21 ms×(0.24°/180°)).

A period of time which is “28 μs” being divided by the number of lightemission areas 211 is set as a delay time. The delay time of this caseis 1 μs (28 μs÷28). While the first rotary mirror 24 rotates for 0.24°with the delay time as 1 μs, the light emission areas 211 arepulse-lighted serially from the top. That is, in a period of time (28μs) in which the first rotary mirror 24 rotates by 0.24°, the lightemission areas 211 are pulse-lighted while being switched serially fromA (1) to A (28) every 1 μs. By performing such processing, the detectionregion can be scanned with the detection light Li. When scanning of thedetection region is performed by lighting the light emission areas 211serially from A (1) to A (28) in the period of time in which the firstrotary mirror 24 rotates for 0.24°, all pieces of object information inthe vertical direction (Z-axis direction) included in the visual fieldregion can be acquired.

Here, a period of time, in which one of the light emission areas 211included in the light source 21 is pulse-lighted, is about 20 ns. FIG.34 is a timing chart illustrating a relationship between a scanning timearound one reflection surface of the first rotary mirror 24 and lightemission timing of the light emission areas 211. As illustrated in FIG.34, when object detection processing in the whole visual field region isexecuted in a scanning time of one reflection surface of the firstrotary mirror 24, a lighting time of one light emission area 211 is 20ns. That is, a period of time until the next light emission area 211 islighted is 980 ns (1 μs-20 ns).

Thus, according to a spatial information acquiring method executed inthe laser radar 20, it is not necessary to consider a problem ofthermal/electrical crosstalk.

Object Information Acquiring Processing

Next, object information acquiring processing executed in the laserradar 20 will be described. FIG. 35 is a flowchart illustrating anexample of a flow of the object information acquiring processingexecuted by the object information acquiring unit 203. As illustrated inFIG. 35, processing steps will be referred to as S401, S402, and thelike.

The object information acquiring processing described in the followingis repeatedly executed by the object information acquiring unit 203 atevery predetermined timing (such as every 21 ms) until an operationpower source of the laser radar 20 is turned off.

First, in the object information acquiring unit 203, initializationprocessing of a variable i for specifying a light emission area 211 isexecuted (S401). In the initialization processing, a value “1” is set asthe variable i.

Next, in the object information acquiring unit 203, processing to selecta light emission area 211 corresponding to the variable i is executed(S402). Here, a light emission area 211 corresponding to A (i) isselected and lighted, and the detection light Li is emitted.

Next, in the object information acquiring unit 203, processing todetermine whether the reflected light Lr from the object 100 is receivedwithin a predetermined period of time is executed (S403). Note that the“predetermined period of time” is, for example, 2 μs. However, the“predetermined period of time” is not limited to 2 μs.

In the object information acquiring unit 203, when it is determined thatthe reflected light Lr from the object 100 is received within thepredetermined period of time (YES in S403), flag information indicatingthat “there is an object” is generated (S404).

Next, in the object information acquiring unit 203, distance acquiringprocessing to acquire a distance to the object 100 is executed (S405).The distance acquiring processing (S405) is processing to calculate adistance to the object 100 in the object information acquiring unit 203based on lighting timing of the light source 21 (timing of emittingdetection light Li from light source 21) and timing of receiving thereflected light Lr in the photodetector 29.

In the object information acquiring unit 203, when it is determined thatthe reflected light Lr from the object 100 is not received in thepredetermined period of time (NO in S403), flag information indicatingthat “there is no object” is generated (S406).

Next, information storing processing to associate a value of thevariable i, a flag indicating presence/absence of the object 100, acalculated distance to the object 100, and detection time with eachother and to store the associated information into a storage unit (notillustrated) included in the object information acquiring unit 203 isexecuted (S407).

Next, determination processing to determine whether the variable i hasreached an upper limit is executed (S408). When the value of thevariable i is smaller than 28 (YES in S408), adding processing to thevariable i is executed (S410) and processing goes back to S402.Hereinafter, until the determination in S408 is affirmed, the processingof S402 to S408 is repeatedly executed.

When the value of the variable i is equal to or larger than 28 (NO inS408), processing goes to the object information acquiring processing(S409).

The object information acquiring processing (S409) is processing toacquire object information based on the information stored into thestorage unit of the object information acquiring unit 203. In the objectinformation acquiring unit 203, when presence/absence of the object 100and a distance to the object 100, in respect to the whole visual fieldregion, which are stored in the storage unit are read and when there isthe object 100, object information such as a position of the object 100,a size of the object 100, and a shape of the object 100 is acquired. Theacquired object information is stored into the memory 50 with thedetection time.

As described above, in the object information acquiring unit 203, theobject information acquiring processing is executed.

Also, the monitoring apparatus 10 which is a sensing apparatus includesthe main control apparatus 40, the memory 50, and the sound/alarmgeneration apparatus 60.

As described above, the laser radar 20 includes the light emittingsystem 201, the light detecting system 202, the object informationacquiring unit 203, and the like.

The light emitting system 201 includes the light source 21, the couplinglens 22, the first reflection mirror 23, the first rotary mirror 24, andthe like. The light detecting system 202 includes the second rotarymirror 26, the second reflection mirror 27, the imaging forming lens 28,the photodetector 29, and the like.

The light source 21 includes the plurality of light emission areas 211arranged at regular intervals in the Z-axis direction. Each of the lightemission areas 211 includes the plurality of light emission units 2111arranged two-dimensionally. In such a manner, by forming each of thelight emission areas 211 by integrating the plurality of light emissionunits 2111, intensity of the detection light Li emitted from the lightemitting system 201 can be increased. Thus, according to the laser radar20, it is possible to make a detectable distance to the object 100longer.

Also, according to a detection region divided in the vertical direction(Z-axis direction), the object information acquiring unit 203 determinesa light emission area 211 to be lighted. That is, according to anemitting direction of the detection light Li on the ZX plane, the objectinformation acquiring unit 203 determines a light emission area 211 tobe lighted among the plurality of light emission areas 211. Thus,according to the laser radar 20, the number of times of division ofdetection in the vertical direction (Z-axis direction) can be improved,and at the same time, duration of the light source 21 can be madelonger.

Also, based on lighting timing of the light source 21 and lightreceiving timing in the photodetector 29, the object informationacquiring unit 203 acquires a distance to the object 100 for each of thedetection regions divided in the vertical direction (Z-axis direction).Moreover, the object information acquiring unit 203 acquires objectinformation based on a distance to the object 100 in each of thedetection regions divided in the vertical direction (Z-axis direction).Thus, according to the laser radar 20, object information can beacquired accurately.

Also, the object information acquiring unit 203 can acquire a distanceto the object 100 in each emitting direction of the detection light Liemitted to each of the detection regions divided in the verticaldirection (Z-axis direction) and can acquire a shape of the object 100.

Also, since the monitoring apparatus 10 includes the laser radar 20,object information and movement information can be calculatedaccurately.

Note that in the above described embodiment, a case where the lightemitting system 201 is arranged on the +Z side of the light detectingsystem 202 has been described but the present invention is not limitedthereto.

Also, in the above described embodiment, a case where a shape of each ofthe light emission areas 211 is a square has been described but thepresent invention is not limited thereto.

Also, in the above described embodiment, a case where a shape of each ofthe light emission units 2111 is a square has been described but thepresent invention is not limited thereto.

Also, in the above described embodiment, a case where each of the firstrotary mirror 24 and the second rotary mirror 26 includes fourreflection surfaces has been described but the present invention is notlimited thereto.

Also, in the above described embodiment, a rotation mechanism to makethe laser radar 20 rotate around the Z-axis may be included.

Also, in the above described embodiment, positions of the coupling lens22 and the imaging forming lens 28 are not limited to the positionsillustrated in the first arrangement example and the second arrangementexample.

Also, in the above described embodiment, a configuration of the lightsource 21 is not limited to a configuration example illustrated in eachof the first arrangement example and the second arrangement example.

Also, in the above described embodiment, a case where the light source21 includes 28 light emission areas 211 has been described but thepresent invention is not limited thereto. The number of light emissionareas 211 only needs to be determined according to a requested size of adetection region in the Z-axis direction.

Also, in the above described embodiment, a case where 250 light emissionunits 2111 are arrayed in the Y-axis direction and 250 light emissionunits 2111 are arrayed in the Z-axis direction in one light emissionarea 211 has been described but the present invention is not limitedthereto.

Also, in the above described embodiment, a case where the number oflight emission units 2111 in the Y-axis direction and the number oflight emission units 2111 in the Z-axis direction are identical to eachother in each of the light emission areas 211 has been described but thepresent invention is not limited thereto.

Also, in the above described embodiment, a case where the plurality oflight emission units 2111 is arrayed two-dimensionally in each of thelight emission areas 211 has been described but the present invention isnot limited thereto. The plurality of light emission units 2111 may bearrayed either in the Y-axis direction and the Z-axis direction.

Also, in the above described embodiment, a case where d2 is about 0.02mm, d3 is about 0.7 μm, and d4 is about 1 μm has been described but thepresent invention is not limited thereto.

Also, in the above described embodiment, the focal length (f1) of thecoupling lens 22 and the focal length (f2) of the imaging forming lens28 may be identical to each other. In this case, the coupling lens 22and the imaging forming lens 28 can be commonalized and a cost can bereduced.

Also, in the above described embodiment, a part of the processingexecuted in the object information acquiring unit 203 can be executed inthe main control apparatus 40. Also, a part of the processing executedin the main control apparatus 40 may be executed in the objectinformation acquiring unit 203.

Also, in the above described embodiment, as illustrated in FIG. 37 andFIG. 38, the first rotary mirror 24 and the second rotary mirror 26 maybe integrated.

Also, in the above described embodiment, a case where the monitoringapparatus 10 includes one laser radar 20 has been described but thepresent invention is not limited thereto. A plurality of laser radars 20may be included according to a size of the vehicle 1 and a monitoredregion.

Also, in the above described embodiment, a case where the laser radar 20is used in the monitoring apparatus 10 to monitor a moving direction ofthe vehicle 1 has been described but the present invention is notlimited thereto. For example, the laser radar 20 may be used in anapparatus to monitor a backside or a side of the vehicle 1.

Moreover, the laser radar 20 may also be used in a sensing apparatusother than that for a vehicle. In this case, the main control apparatus40 outputs alarm information corresponding to a purpose of the sensing.

Also, the laser radar 20 may be used only to detect presence/absence ofthe object 100.

Also, the laser radar 20 may be used for a purpose other than a sensingapparatus (such as distance measuring apparatus or shape measuringapparatus).

According to the present invention, it is possible to divide a visualfield region in an up-down direction (vertical direction) and to improveresolution of the detection region.

Although the invention has been described with respect to specificembodiments for a complete and clear disclosure, the appended claims arenot to be thus limited but are to be construed as embodying allmodifications and alternative constructions that may occur to oneskilled in the art that fairly fall within the basic teaching herein setforth.

What is claimed is:
 1. An object detecting apparatus comprising: a lightprojector that includes an array light source in which each of aplurality of light emission areas emits light; and a coupling lens thatcouples light emitted from the light emission areas; an optical scannerthat performs scanning with the light, which is emitted from the lightprojector, in a first direction; a light receiver that includes aphotodetector and an imaging forming lens and receives reflected light,with which scanning is performed, being reflected by an object, thecoupling lens being arranged at a position which is away from the arraylight source by a distance corresponding to a focal length of thecoupling lens when seen from the array light source, the photodetectorbeing arranged at a position farther than a focal length of the imagingforming lens when seen from the imaging forming lens; and a processor todetect a presence/absence of the object based on emission timing atwhich the light is emitted from the light projector and light receivingtiming at which the light receiver receives the reflected light.
 2. Theobject detecting apparatus according to claim 1, wherein a formedposition of a conjugate image of the photodetector by the imagingforming lens is set as the shortest detection distance.
 3. The objectdetecting apparatus according to claim 1, wherein the light emissionareas are arrayed in a direction different from the first direction, andthe processor determines a light emission area to be lighted among theplurality of light emission areas according to a detection region by thelight used for the scanning.
 4. The object detecting apparatus accordingto claim 1, wherein each of the light emission areas is an aggregationof a plurality of light emission units.
 5. The object detectingapparatus according to claim 1, wherein the optical scanner is a polygonmirror including a plurality of reflection surfaces, and light emittedfrom the different light emission areas are respectively projected onthe reflection surfaces.
 6. The object detecting apparatus according toclaim 1, wherein the optical scanner is a polygon mirror including aplurality of reflection surfaces, and light emitted from the differentlight emission areas are projected on one of the reflection surfaceswhile the one reflection surface performs scanning.
 7. The objectdetecting apparatus according to claim 6, wherein a range scanned by theone reflection surface is divided into a plurality of regions, and thelight emission areas to project the light are switched in one of theplurality of regions.
 8. The object detecting apparatus according toclaim 1, wherein when detecting the object, the processor calculates adistance to the object based on emission timing at which the light isemitted from the light projector and light receiving timing at which thelight receiver receives the reflected light.
 9. The object detectingapparatus according to claim 8, wherein the processor acquires a shapeof the object based on a distance to the object in each emittingdirection of the light emitted from the optical scanner.
 10. An objectdetecting apparatus comprising: a light projector that includes an arraylight source in which each of a plurality of light emission areas emitslight; and a coupling lens that couples light emitted from the lightemission areas; an optical scanner that performs scanning with thelight, which is emitted from the light projector, in a first direction;a light receiver that includes a photodetector and an imaging forminglens and receives reflected light, with which scanning is performed,being reflected by an object, the coupling lens being arranged at aposition farther than a focal length of the coupling lens when seen fromthe array light source, the photodetector being arranged at a positionwhich is away from the imaging forming lens by a distance correspondingto the focal length of the imaging forming lens when seen from theimaging forming lens; and a processor to detect a presence/absence ofthe object based on emission timing at which the light is emitted fromthe light projector and light receiving timing at which the lightreceiver receives the reflected light.
 11. The object detectingapparatus according to claim 10, wherein the light emission areas arearrayed in a direction different from the first direction, and theprocessor determines a light emission area to be lighted among theplurality of light emission areas according to a detection region by thelight used for the scanning.
 12. The object detecting apparatusaccording to claim 10, wherein each of the light emission areas is anaggregation of a plurality of light emission units.
 13. The objectdetecting apparatus according to claim 10, wherein the optical scanneris a polygon mirror including a plurality of reflection surfaces, andlight emitted from the different light emission areas are respectivelyprojected on the reflection surfaces.
 14. The object detecting apparatusaccording to claim 10, wherein the optical scanner is a polygon mirrorincluding a plurality of reflection surfaces, and light emitted from thedifferent light emission areas are projected on one of the reflectionsurfaces while the one reflection surface performs scanning.
 15. Theobject detecting apparatus according to claim 14, wherein a rangescanned by the one reflection surface is divided into a plurality ofregions, and the light emission areas to project the light are switchedin one of the plurality of regions.
 16. The object detecting apparatusaccording to claim 10, wherein when detecting the object, the processorcalculates a distance to the object based on emission timing at whichthe light is emitted from the light projector and light receiving timingat which the light receiver receives the reflected light.
 17. The objectdetecting apparatus according to claim 16, wherein the processoracquires a shape of the object based on a distance to the object in eachemitting direction of the light emitted from the optical scanner.